This paper focuses on the multi-objective optimization of friction stir welding process parameters. Three input variables, including the axial load (AL), tool rotation speed (RS), and tool tilt angle (TA), were selected to optimize the mechanical characteristics of Al-2024 friction stir-welded (FSW) joints. The ultimate tensile strength (UTS) and impact energy (IE) were selected as output responses to measure the mechanical characteristics of Al-2024 FSW joints. A total of nine experiments, using the L9 orthogonal array as part of the Taguchi method, were performed to determine the significance of the process parameters. Gray relational analysis (GRA) was employed to conduct the multi-objective optimization of these combinations of process parameters. The results of the analysis of variance (ANOVA) showed that the AL has the most significant effect on the UTS and IE of Al-2024 FSW joints, followed by the TA and RS. The Taguchi-based GRA analysis revealed that an AL of 10 KN, a TA of 2 degrees, and an RS of 1500 rpm resulted in an optimal UTS of 333.06 MPa and an IE of 40.62 Joules. In these optimal experimental settings, optical microscopy analysis revealed the presence of a recrystallized fine-grain structure in the heat-affected zone of the welded region.

This study aims to analyze the performance of dissimilar titanium alloy Ti-5Al-2.5 Sn and stainless-steel SS 304 joints using three non-destructive testing (NDT) methods such as radiographic testing, visual and microstructural evaluation. Gas tungsten arc welding (GTAW) was performed to join the base metals by incorporating the multi-interlayer of Cu-Nb. The performance of dissimilar joints was evaluated in terms of quality and strength at a welding current of 40 and 60 amperes, and a fixed gas flow rate and welding speed of 20 lit/min and 150 mm/min, respectively. Radiography and visual results indicated severe cracks, voids and incomplete fusion in the specimen welded at a higher current and no such flaws in the specimen welded at a low current. Microstructural results revealed that a dendritic structure was achieved in the fusion zone at a low current that enhanced the ultimate tensile strength (UTS) to 248 MPa while brittle cracks were observed at the Ti-Cu side at higher currents, which reduced the strength to 160 MPa.

The joining of titanium and stainless steel is challenging with conventional filler metals due to the formation of Fe-Ti intermetallic compounds (IMCs). Therefore, a filler that is compatible with both metals is necessary to avoid these IMCs and enhance the mechanical properties of Ti-SS joint. This research aims to investigate the effect of novel Nb-Cu composite filler on mechanical and microstructure properties of TA7-SS304 dissimilar hybrid composite joints using gas tungsten arc welding (GTAW) process. The mechanical properties: ultimate tensile strength (UTS) and micro hardness have been analyzed and assessed through the microstructure of weld interfaces and fracture zones. Results revealed that welding current (I) affects the UTS significantly whereas micro hardness is greatly influenced by welding speed (Ws). The maximum UTS of 293 MPa and micro hardness of 100 HV as well as minimum tensile residual stresses of 180 MPa and 170 MPa on SS 304 and TA7 sides, respectively have been attained at optimal parameters of I = 40 A, Ws = 150 mm/min and GFR = 18 lit/min. SEM and EDS analysis showed that presence of Cu and Nb solid solutions in the fusion zone contributed to improvement in UTS. Ductile fracture surface with no prominent defects is obtained at optimal combination, while brittle fracture with voids and cavities is observed for low-strength joints. X-ray diffraction analysis depicted that the formation of TiFe, Ti 2 Fe, and TiFe 2 compounds and direct mixing of base metals have been successfully inhibited by using Nb-Cu composite filler which improved the Ti-SS bonding.

Objectives. Current research aims to identify factors that affect the occupational safety climate in university laboratories despite their perception as low-risk areas compared to industrial environments. Methods. A safety climate survey was conducted in science laboratories across various engineering universities in Pakistan. The survey questionnaire was administered to 406 personnel, and a quantitative method for analysis was selected to examine the socio-demographic variables. A 5-point Likert scale (1 = strongly disagree to 5 = strongly agree) was used to perceive responses from participants. Additionally, a scale reliability test was conducted, and multivariate analysis of variance was performed to determine the relationship between selected dependent and independent variables. Results. The study found an overall safety climate score of 3.16 +/- 0.55, indicating a moderate to high perception of safety on a scale of 1-5. Parameters such as role in the laboratory, departments/disciplines, accident experience and safety training significantly affected the safety climate score, while gender, age group, duration in university and accident witnessing did not. Conclusion. Upper management involvement, safety communication and direct supervision are crucial for improving the safety climate of university laboratories. The study recommends the consideration of the identified significant safety climate dimensions in laboratory safety policy-making at academic institutes.

This research focuses on optimizing the mechanical and electrical properties of 7075 Al/Cu composite joints produced through the squeeze casting process. The effect of three key input parameters, such as copper bar preheating temperature (TC), melt temperature (TM), and squeeze pressure (SP) on electrical resistance (ER), micro-hardness (MH), and ultimate tensile strength (UTS) has been analyzed. The response surface methodology (RSM) and artificial neural network (ANN) methods have been used to structure the input parameters, which allows the modeling of the input parameters to predict the optimal output response. Analysis of variance results indicated that TM significantly influenced the ER, whereas UTS and MH are predominantly affected by SP. Optimal values of the UTS of 60.10 MPa, MH of 86.11 HV, and ER of 2.240 µΩ have been achieved at TC of 300 °C, TM of 780 °C, and SP of 90 MPa. The scanning electron microscope analysis proved that the diffusion rate of Cu atom into the Al melt has increased significantly at the optimal experimental settings, which has prominently improved the electro-mechanical properties of the Al/Cu composite joints. The fractography analysis revealed a brittle fracture surface with a substantially flat facet morphology at optimal conditions. In contrast, energy-dispersive spectroscopy revealed a zinc content of 0.83

The current study aims to investigate the effect of the hybrid thermal tensioning technique transient thermal tensioning and trailing intensive cooling (TTT–TIC) on residual stresses and distortion of titanium Ti-5Al-2.5Sn and stainless steel 304 gas tungsten arc welded (GTAW) joints using Nb–Cu composite filler. The two preheating oxyacetylene torches are used for in-situ heating at TTT condition whereas compressed CO2 has been employed for in-situ trailing cooling of weld at TIC condition. The residual stresses and distortion have been evaluated at the distance between preheating torches (DA) in the case of TTT, the distance between the cooling source and the welding torch (DB) in case of TIC, and optimal distances DA and DB in case of hybrid TTT–TIC condition. The minimum values of tensile residual stresses and distortion of 98 MPa and 0.904 mmm on SS side, and 84 MPa and 0.425 mm on Ti side have been obtained at TTT–TIC condition. A significant percentage reduction in tensile residual stresses has been attained at novel TTT–TIC of 60

Despite efforts made over the past two decades, Pakistan continues to face electricity crises. The heavy reliance on fossil fuels, which make up 60% of the country’s energy mix, has raised concerns about energy security and environmental degradation due to greenhouse gas (GHG) emissions. Developing effective electricity generation scenarios has been challenging for policymakers and researchers, despite the steady increase in electricity demand. The LEAP software was used in this study to forecast the country’s power demand, and four supply-side scenarios were constructed and examined for the years 2018 through 2040. These scenarios include a baseline scenario, a renewable energy scenario, a more renewable energy scenario, and a near-zero emission scenario, focusing on electricity generation and carbon emissions. The study’s findings, projecting into 2040, indicate that the renewable energy scenarios are environmentally sustainable, with lower GHG emissions compared to the baseline scenario. According to the findings of this study, it is projected that around 615 TWh (terawatt-hours) of renewable energy and nuclear energy will be necessary by the year 2040. The anticipated contributions include 393 TWh from hydroelectric energy, 57 TWh from wind energy, 41 TWh from solar energy, and 62 TWh from other renewable sources. The surge in renewable energy is forecasted to bring near-zero CO2 emissions by 2040, a pivotal step toward a sustainable energy future. A projected energy generation of 615 TWh is expected, which adequately meets the country’s energy demand. Transition to renewable energy is critical for addressing Pakistan’s increasing electricity demands, emphasizing both energy security and environmental sustainability.

This study aims to analyze the effect of 70-30 Cu-Ni filler metal on mechanical and microstructural properties of Al 2024 and stainless steel 304 hybrid joints fabricated through the gas tungsten arc welding technique. The mechanical properties, i.e., tensile strength and microhardness, of Al-SS joints have been analyzed and evaluated through joint interfacial microstructure analysis. The optimum tensile strength (155.746 MPa) has been obtained at welding current ranges between 75 and 80 A, welding speed of 110–115 mm/min, and gas flow rate of 9.75-10 L/min, whereas maximum microhardness (300 HV) at welding speed of 115-120 mm/min, welding current of 70-75 A, and gas flow rate of 9.5-10 L/min. The fine equiaxed dendrites at the interface of the aluminum weld zone and the thin interfacial layer at the SS304 weld zone interface contributed to the higher tensile strength. Scanning electron microscopy, energy-dispersive spectroscopy, and x-ray diffraction reveal the ductile CuAl, NiAl 3 , and NiAl phases instead of Fe-Al brittle phase, improving hybrid bonding between Al 2024 and SS 304. The dimples and tear ridges microstructure have been observed for high-strength joint, while cracks and cavities on the fracture surface indicate its brittleness and low strength (102 MPa).

This study aims to evaluate the microstructure and mechanical behavior of aluminum 2024 and stainless steel 304 dissimilar joints. The gas tungsten arc welding (GTAW) process has been employed to weld base metals by inserting copper-nickel-based (Cu-10%Ni) filler metal. The effects of GTAW parameters such as welding current, welding speed, and gas flow on microstructure and tensile strength have been analyzed through the Taguchi method. Results revealed that tensile strength is primarily influenced by welding current, followed by speed and gas flow rate. The excellent joint strength of 138 MPa has been achieved by using Cu-10%Ni filler metal. The optimal combination of parameters, i.e., welding current of level 2 (80 A), welding speed of level 1 (100 mm/min), and gas flow rate of level 3 (10 l/min), has been obtained through SN ratio optimization. Microstructure and EDS analysis depicted that the weld zone of a high-strength joint contained fine dendrites and CuAl and NiAl solid solutions, while the weld zone of a low-strength joint featured coarse dendrites and brittle FeAl phases.

The primary objective of this study is to evaluate the adaptability and inclination of industrial sectors of Pakistan with respect to Industry 4.0. A questionnaire with nine questions was developed and disseminated to 20 sampled industries. To analyze the variability in responses, a one-way analysis of variance test was used. The statistical analysis revealed that there is an awareness of the basic concept behind Industry 4.0 in Pakistani industries, but there is a reluctance to adopt digitization and to shift from conventional production systems. This study will be helpful and will provide a guide for new and already existing enterprises for achieving Industry 4.0 requisite attributes precisely.

The effects of drilling process parameters, such as drill diameter and feed rate, on the delamination of holes has been examined while drilling Carbon-Fiber-Reinforced Plastics and aluminum (CFRP/Al2219-T6). The stack method was employed while drilling in order to reduce the defects in the drilling process and enhance the quality of the holes produced. A total of nine experiments were performed using the central composite design. An analysis of variance (ANOVA) revealed that feed rate and drill size have significant effects on the delamination of holes. The experimental results show that the minimum delamination value (1.018) was obtained at a feed rate of 26.5 mm/min and with a drill diameter of 6.5 mm.

Developing countries are facing challenges to adopt the Industry 4.0 in their manufacturing sector. One of the reasons is lacking technological and maturity models' compatibility to assess the current state of maturity and readiness level. This empirical research has presented a maturity model based on the IMPULS models developed by the German Association of Mechanical Engineers and the Singapore Smart Industry Readiness Index with some modifications. A comprehensive and compatible lean modified manufacturing maturity model for Industry 4.0 (LM4I4.0) has been developed and validated. The proposed model has add-on dimension of the lean philosophy. This modification provides the facility to integrate the two main manufacturing paradigms of lean and Industry 4.0. The developed LM4I4.0 has been validated in fifty manufacturing industries of Pakistan and results have been presented in the data analysis format. The data mining, dimension cluster analysis, and computation of data shows that the proposed model is compatible for the developing country. Moreover, the results and analysis show that the maturity level of Pakistani manufacturing is 3.39, which means companies are immature in context of Industry 4.0. The proposed methodology may be used to conduct self-evaluations and enable businesses to undertake self-assessments in order to align themselves with Industry 4.0 in a systematic way. It will, therefore, provide a direction to formulate the enterprise transformation strategies in Industry 4.0 paradigm.

Al7075−Cu composite joints were prepared by the squeeze overcast process. The effects of melt temperature, die temperature, and squeeze pressure on hardness and ultimate tensile strength (UTS) of squeeze overcast Al7075−Cu composite joints were studied. The experimental results depict that squeeze pressure is the most significant process parameter affecting the hardness and UTS. The optimal values of UTS (48 MPa) and hardness (76 HRB) are achieved at a melt temperature of 800 °C, a die temperature of 250 °C, and a squeeze pressure of 90 MPa. Scanning electron microscopy (SEM) shows that fractured surfaces show flat-faced morphology at the optimal experimental condition. Energy-dispersive spectroscopy (EDS) analysis depicts that the atomic weight percentage of Zn decreases with an increase in melt temperature and squeeze pressure. The optimal mechanical properties of the Al7075−Cu overcast joint were achieved at the Al2Cu eutectic phase due to the large number of copper atoms that dispersed into the aluminum melt during the solidification process and the formation of strong intermetallic bonds. Gray relational analysis integrated with the Taguchi method was used to develop an optimal set of control variables for multi-response parametric optimization. Confirmatory tests were performed to validate the effectiveness of the employed technique. The manufacturing of squeeze overcast Al7075−Cu composite joints at optimal process parameters delivers a great indication to acknowledge a new method for foundry practitioners to manufacture materials with superior mechanical properties.

Products manufactured by joining titanium and stainless steel are of great attention to the modern-day industries (aerospace and nuclear) due to their several benefits like high strength, low cost, and corrosion resistance. However, it is difficult to join these alloys owing to the formation of TiFe, Ti 2 Fe, and TiFe 2 compounds which damage their mechanical properties. This study aims to evaluate the microstructural and mechanical properties of titanium alloy Ti-5Al-2.5Sn and stainless steel 304 joints. Joining was performed through pulse–gas tungsten arc welding (P-GTAW) by inserting the Nb-Cu multi-interlayer. The effects of welding speed, two multi-interlayer application modes, and arc offset on the microstructure and mechanical properties such as tensile strength and microhardness were investigated. The mechanical properties were evaluated through tensile and hardness tests while microstructural analysis using scanning electron microscopy (SEM) supported by electron dispersive spectroscopy (EDS). The results revealed that sound and high-quality welds were achieved using a multi-interlayer, which inhibited the formation of TiFe, Ti 2 Fe, and TiFe 2 brittle intermetallic compounds (IMCs). Maximum joint strength of 327 MPa was achieved at a welding speed of 200 mm min −1 , mode of multi-interlayer (Nb used as a foil and Cu as a wire) at no arc offsetting, whereas a low joint strength was obtained in the multi-interlayer mode (Nb and Cu both as foils), and arc offset towards SS. The SEM and EDS results revealed that a Cu solid solution was obtained in the fusion zone, which improved the tensile strength. Joint fracture surface analysis indicated that ductile fracture was obtained for high-strength and brittle fracture for the low-strength weld. It is evident that high hardness (400 HV) was obtained at a low welding speed (150 mm min −1 ) and an arc offset to the stainless steel side owing to the formation of TiCu and Ti 2 Cu phases, as revealed by the x-ray diffraction phase analysis.

Dry machining of aluminum (Al) 2024 alloy has been performed with four different cutting inserts (cemented carbide, titanium nitride (TiN) coated, titanium aluminum nitride (TiAlN) coated, and polycrystalline diamond (PCD) coated), and their performance is assessed for tool wear and workpiece surface roughness. Design of experiments and response surface methodology (RSM) was performed to optimize the cutting parameters. TiAlN coated inserts presented an average ≈ 21%, ≈ 36%, and ≈ 58% less tool wear than the uncoated cemented carbide, TiN and PCD coated inserts, respectively. While TiN coated inserts exhibited an average ≈ 17%, ≈ 37%, and ≈ 42% less workpiece surface roughness than the uncoated cemented carbide, TiAlN, and PCD coated inserts, respectively. PCD coated inserts have greater mechanical properties, but due to the poor adhesion strength of the coating, it performed worst regarding tool wear and workpiece surface roughness. Energy dispersive X-ray spectroscopy (EDX) analysis of the chips validated our findings that the adhesion of coated tools is also very important for the evaluation of machining performance other than mechanical properties. It is concluded that the mechanical properties and adhesion of the coated tools are both important in assessing the tool wear and workpiece surface roughness. Also, the research community and industry need to consider adhesion strength of the coated tools for better machining performance.

The requirement of cost-effective and ecological production systems is crucial in the competitive market. In this regard, the focus is shifted towards sustainable and cleaner machining processes. Besides the clean technologies, effective parametric control is required for machining materials (such as High Strength Low Alloy Steels) specifically designed for high strength applications having superior physio-chemical properties. Therefore, the machinability complexities require optimized solutions to reduce temperature elevation and tooling costs and improve machining of these materials. Complying to the market needs, this research examines the effectiveness of nanofluid on tool life, wear mechanisms, surface roughness (Ra), surface morphology, and material removal rate (MRR) in turning of 30CrMnSiA (HSLA) using minimum quantity lubrication (MQL) and SiO 2 -H 2 O nanofluids (NF-MQL). A systematic investigation based on physical phenomena involved is carried out considering four process parameters (cutting speed (V C ), feed rate (F r ), depth of cut (D OC ), and mode of lubrication for machining. F r is found as the vital parameter for surface roughness while MRR is highly influenced by D OC regardless of lubrication approach. One-step sustainability technique is applied, in which process variables used for roughing conditions are analogous to attain surface comparable to finished machining without compromising process efficiency and demonstrate its feasibility through optimal settings under NF-MQL. Multi-response optimization proved the NF-MQL machining condition as the best alternative which result in 28.34% and 5.09% improvements for surface roughness and MRR, respectively. Moreover, the use of SiO 2 is recommended over MQL due to lower energy consumption, low tool wear, and better surface integrity, sustainable liquid, and related costs.

Friction and wear are very crucial aspects of the performance, service life, and the operational costs for a mechanical component or equipment. To reduce the friction and wear at the interface of the sliding or mating parts, different conventional binary coatings like TiN, CrN, TiC, etc., have been used in the last two decades. But ternary nitride coatings have replaced the binary coatings due to better tribo-mechanical properties. Now, ternary nitride coatings are being extensively used in several fields such as cutting tools, machinery parts, orthopedic implants, microelectronics, marine equipment, decorative purposes, automotive, aerospace industry, etc. Many researchers have developed and investigated the ternary nitride coatings for different applications. Nonetheless, there is a huge research potential in the development and optimization of the tribo-mechanical properties of the ternary nitride coatings. Therefore, tribo-mechanical studies of the ternary nitride coatings are needed for fostering the new industrial applications. This paper is focused to summarize and compare the tribo-mechanical properties of the ternary nitride coatings comprehensively and aims to explore the novel research directions in the development of the ternary nitride coatings.

Gas tungsten arc welding (GTAW) is considered a well-established process in the manufacturing industry. Despite, certain challenges associated with high hardness of heat affected zone and cold cracking susceptibility of joints, are the main barriers for this process to be implemented successfully within high integrity structure. By using a combined procedure of experiments and modelling (response surface methodology (RSM) and multi-objective optimization: multi-objective genetic algorithm (MOGA)) allows obtaining good enhancement over uniform heating, cooling and the heat-affected zone which enable major progress in obtaining high quality welded parts. Therefore, this research study combines the experiments and modelling in a systematic manner considering for the first type the pre-heated treatment and without-pre-heating conditions of GTAW manufacturing. It leads to optimizing the process parameters of GTAW when manufacturing AISI 1045 medium carbon steel. The effects of critical parameters i.e. welding current: WC, welding speed: WS, and gas flow rate: GFR on the mechanical properties (ultimate tensile strength (UTS) and hardness) were investigated and evaluated against the microstructure of weld fracture. The multi-objective genetic algorithm corroborated with experimental observation enables to obtain a maximum UTS of approx. 625 MPa and hardness of 80.19 HRB for preheat condition. The results highlight an improvement in UTS of 0.2%-6.7% and a decrease in hardness of 0.1%-21.5% by implementing the preheating condition.

The emissions from coal power plants have serious implication on the environment protection, and there is an increasing effort around the globe to control these emissions by the flue gas cleaning technologies. This research was carried out on the limestone forced oxidation (LSFO) flue gas desulfurization (FGD) system installed at the 2*660 MW supercritical coal-fired power plant. Nine input variables of the FGD system: pH, inlet sulfur dioxide (SO2), inlet temperature, inlet nitrogen oxide (NOx), inlet O-2, oxidation air, absorber slurry density, inlet humidity, and inlet dust were used for the development of effective neural network process models for a comprehensive emission analysis constituting outlet SO2, outlet Hg, outlet NOx, and outlet dust emissions from the LSFO FGD system. Monte Carlo experiments were conducted on the artificial neural network process models to investigate the relationships between the input control variables and output variables. Accordingly, optimum operating ranges of all input control variables were recommended. Operating the LSFO FGD system under optimum conditions, nearly 35% and 24% reduction in SO(2)emissions are possible at inlet SO(2)values of 1500 mg/m(3)and 1800 mg/m(3), respectively, as compared to general operating conditions. Similarly, nearly 42% and 28% reduction in Hg emissions are possible at inlet SO(2)values of 1500 mg/m(3)and 1800 mg/m(3), respectively, as compared to general operating conditions. The findings are useful for minimizing the emissions from coal power plants and the development of optimum operating strategies for the LSFO FGD system.

Titanium nitride (TiN) is a hard-ceramic material having excellent wear and corrosion resistance properties. In this study, TiN coating has been deposited on carbide cutting inserts by a low-temperature cathodic arc phsical vapor deposition (PVD) system. Comparative analysis of machining performance, based on tool life and work piece surface roughness, has been done between the TiN-coated carbide cutting inserts and uncoated carbide cutting inserts in dry machining of medium carbon AISI 1045 steel. Design of experiments (DOE) technique along with response surface regression has been used for the optimization of machining parameters. The most significant factor affecting the surface roughness of the work piece in dry machining was found to be the feed rate. TiN-coated carbide cutting inserts showed 15% improvement in the surface roughness of work piece and 60% improvement in tool life as compared to uncoated carbide cutting inserts.